By G.P. Thomas
Artistic impression of a 2D graphene sheet. Image Credit: photos.com
A research team has demonstrated that model cell membranes can be grown outside of the body on graphene sheets, which could provide invaluable benefits to life science research.
The human body contains trillions of cells, the ‘building blocks of life’, which make up who we are. Each of these cells is enveloped by a membrane which protects the inner workings of the cell, letting beneficial substances in and keeping harmful substances out.
It is therefore incredibly beneficial to study these membranes to aid advances in many diverse areas of life sciences, from drug delivery to bio-catalysis.
However, studying these structures inside the human body can be problematic; so much research has gone into producing these membranes on substrates in the lab for ease of accessibility.
Now a research team from the University of Manchester, led by Dr Aravind Vijayaraghavan, and Dr Michael Hirtz at the Karlsruhe Institute of Technology (KIT), have published results in Nature Communications demonstrating how cell membranes can be ‘written’ directly onto substrates of graphene.
The technique used for this writing is known as Lipid Dip-Pen Nanolithography (L-DPN), which is explained in more detail below by Dr. Hirtz.
"The technique utilizes a very sharp tip with an apex in the range of several nanometers as a means to write lipid membranes onto surfaces in a way similar to what a quill pen does with ink on paper.
The small size of the tip and the precision machine controlling it allows of course for much smaller patterns, smaller than cells, and even right down to the nanoscale. By employing arrays of these tips multiple different mixtures of lipids can be written in parallel, allowing for sub-cellular sized patterns with diverse chemical composition."
Using graphene as the surface holds many advantages over other materials currently used, which makes them perfect for developing bio-sensors. Dr Vijayaraghavan explains:
"Firstly, the lipids spread uniformly on graphene to form high-quality membranes. Graphene has unique electronic properties; it is a semi-metal with tuneable conductivity.
"When the lipids contain binding sites such as the enzyme called biotin, we show that it actively binds with a protein called streptavidin. Also, when we use charged lipids, there is charge transfer from the lipids into graphene which changes the doping level in graphene. All of these together can be exploited to produce new types of graphene/lipids based bio-sensors."
The news comes as Professors Sir Andre Geim and Sir Konstantin Novoselov, who jointly won the 2010 Nobel Prize in Physics for work on graphene, were recently offered the freedom of the city of Manchester, due to their contribution to science.
Original source: University of Manchester